Heat treatment of cold shaped manganese steel articles



Patented Nlar. 29, 1932 V UNITED STATES JOHN HOWE HALL, OF HIGH *BRDQE, NEW JERSEY, ASSIGNOB TO TAYLOR-WHABTON BRIDGE, NEWJEBSEY, A CORPORATION OF IRON AND STEEL COMPANY, OF HIGH NEW JERSEY PATENT. orrlca HEAT TmmNT OF COLD SHAPED MANGANESE STEEL ARTICLES 7 No Drawing.

cold working or shaping and can ,be and are.

employed in the manufacture of articles for wh1ch ordinary manganese steel has failed;

either in-the making of the article or in the service thereof.

A particularly desirable application of such special iron or steel alloys is in the roduction. of coldshaped articles from re s or Wu'esas, for example, woven screens, or of coldshaped articles from sheets oi plates as, for example, military helmets, chutes, grids, etc.

v In the die formin drawing, pressing or other method of col shaping, the metal acquires, as a natural concomitant of cold working, added hardness or stifi'ness which, under different circumstances or conditions, may prove beneficial or detrimental. For exam 1e, the hardness imparted by cold drawing of the sheet to helmet form mi ht attain to a degree of brittleness such t at when fired upon under regulation conditions of distance and caliber of wea on, the helmet would be punctured or bad y cracked.

The object of my invention is to improve I the manufacture of articles formed by cold working from special iron or steel alloys. of-

the character indicated, by controlling the effect of cold working so that the finished articles will be usefully stifi and hard without being either too brittle or too soft; and the nature of the invention consists in the method hereinafter stated of heat treating steel containing, for example, less than one percent of carbon, an efl'ectiveamount up to five per cent nickel, less than decimal fifty per cent silicon and ten to fifteen per cent of manganese; or a steel containing decimal thirty to decimal eighty-five per cent of carbon, an effective amount up to five per cent Application filed February 0', 1930. seriariwo. 426,445.

nickel, less than decifnal fifty per cent silicon, an effective amount up to elght per cent chrome, and ten to fifteen per cent manganese.

Inthe practice of the invention, it is sometimes desirable or expedient, depending uponcircumstances or conditions, to subject the rolled sheet or otherwise formed blank to a preliminary annealing before proceeding further with the cold shapin or partial shaping of the article. For examp e, the blank is heated to a temperature within the range of about 1400 to about 1800 F., cooled in air or water and then subjected to cold shaping by drawing 1 or otherwise. After finish forming-or partial forming, de ending upon its nature, the article is heate to an adequate'temperature, say about 1300- F., held for an effective period, and then cooled in the air. Any further shaping that may be required is thereupon proceeded with by cold worln'ng operations upon the completion of which the article is heated to about 1200 F., held for an effective period and then air cooled.) If a number of cold passes oroperations are requisite to, the finish forming of the article, it is sometimes .expedient or beneficial to interrupt the continuity of the cold workin by heat treating the partially formed artic e at successively decreasing temperatures between say about 1800 F. and 1400? F. 1

The described heat treatment has the effect of obviating undesirable inequalities of-hardness and, without'wholly destroying the influence of cold working, of eliminating superhardness so that the finished article desirable stiffness and hardness wit out bein either too brittle or too soft.

aving described my invention, I claim:

' 1. In the production of articles by cold working iron or steel alloys containin ten to fifteen per cent manganese and up to ve per cent nickel, and in order to correct conditions resulting from superhardening of the article under the influence of cold working, the improvement which consists in heating the article, following severe cold shaping, to a temperature ofabout 1200 F., holding the heat for an effective period, and thereafter cooling.

the article in the air.

ossesses article, the improvement which consists in interrupting the continuity of the cold work- 2. In the production of articles by cold working iron or steel alloys containing ten to fifteen r cent manganese and u to ve per cent nic el and where a number 0 cold passes or operations are required to complete the ing by heat treating the article,[following severe cold shaping, at successivel declining temperatures of from about 1800 to about 1400 F.

3. In the production of articles by cold working iron or steel alloys containin%ten to fifteen per cent manganeseand up to ve per cent nickel, the improvement which consists in subjecting the blank to a preliminary heating at a temperature about 1400' to 1800 F. and then cooling it, cold shaping the article under conditions to avoid superhardening,

heating the finished article to a tem rature of about 1300 F., and then cooling it in the air.

In testimony whereof I aflix my JOHN HO WE sifiature. 

